how to use rails g command in rails 3.1 engine path

rubyonrails-core
1

I use rails3.1 edge. i run rails g model post title:string body:text ,       invoke active_record       create db/migrate/20110710035713_create_posts.rb       create app/models/post.rb       invoke test_unit       create test/unit/post_test.rb       create test/fixtures/posts.yml

but this files were created in test/dummy path,how can i use the rails g command to create files in engine path